Porous hydrophobic gas diffusion electrodes made from electrocatalysts and PTFE (or similar material as binder and hydrophobic component) on a porous conducting support are known for use as fuel cell electrodes and for similar applications.
All the noble metals have been proposed as catalysts, although platinum in the form of high surface area platinum blacks either alone or supported on carbon has been most widely used both for hydrogen oxidation and oxygen reduction.
For hydrogen oxidation in particular, platinum-rhodium catalysts have been used as carbon monoxide tolerant catalysts in acid and platinum-palladium catalysts have been used in alkali to reduce the quantity of expensive platinum. Platinum-ruthenium catalysts have also been proposed in the literature. Ruthenium alone has been reported to be unsatisfactory, although obviously it would be advantageous from a cost standpoint if it could be made to perform as well as platinum or the other platinum group metals or their mixtures or alloys.